Reciprocating pump

Abstract

The reciprocating pump includes a cylinder having an inflow chamber, a reset chamber, an intermediate chamber, and a pressurizing chamber therein, a piston located in the cylinder, a first seal, a second seal, and a third seal arranged in a gap between an inner surface of the cylinder and an outer surface of the piston, a suction check valve coupled to a suction port, an inlet check valve and an outlet check valve disposed in a piston passage, a discharge check valve coupled to a discharge port, and a leakage discharge check valve coupled to a leakage discharge port of the cylinder. The piston has a communication passage that provides a fluid communication between the piston passage and the intermediate chamber.

What is claimed is: 
     
         1 . A reciprocating pump for delivering liquefied gas, comprising:
 a cylinder having an inflow chamber, a reset chamber, an intermediate chamber, and a pressurizing chamber therein;   a piston located in the cylinder;   a first seal, a second seal, and a third seal arranged in a gap between an inner surface of the cylinder and an outer surface of the piston;   a suction check valve coupled to a suction port of the cylinder;   an inlet check valve and an outlet check valve disposed in a piston passage extending through the piston;   a discharge check valve coupled to a discharge port of the cylinder; and   a leakage discharge check valve coupled to a leakage discharge port of the cylinder,   wherein the leakage discharge port communicates with the reset chamber,   the inflow chamber and the reset chamber are partitioned by the first seal,   the reset chamber and the intermediate chamber are partitioned by the second seal,   the intermediate chamber and the pressurizing chamber are partitioned by the third seal, and   the piston has a communication passage that provides a fluid communication between the piston passage and the intermediate chamber.   
     
     
         2 . The reciprocating pump according to  claim 1 , further comprising a shaft seal device configured to seal a gap between a piston rod coupled to the piston and the cylinder. 
     
     
         3 . The reciprocating pump according to  claim 1 , wherein a diameter of the inflow chamber is larger than a diameter of the pressurizing chamber. 
     
     
         4 . The reciprocating pump according to  claim 1 , wherein the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber are arranged in an order of the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber along a longitudinal direction of the cylinder. 
     
     
         1 . A reciprocating pump for delivering liquefied gas, comprising:
 a cylinder having an inflow chamber, a reset chamber, an intermediate chamber, and a pressurizing chamber therein;   a piston located in the cylinder;   a first seal, a second seal, and a third seal arranged in a gap between an inner surface of the cylinder and an outer surface of the piston;   a suction check valve coupled to a suction port of the cylinder;   an inlet check valve and an outlet check valve disposed in a piston passage extending through the piston;   a discharge check valve coupled to a discharge port of the cylinder; and   a leakage discharge check valve coupled to a leakage discharge port of the cylinder,   wherein the leakage discharge port communicates with the reset chamber,   the inflow chamber and the reset chamber are partitioned by the first seal,   the reset chamber and the intermediate chamber are partitioned by the second seal,   the intermediate chamber and the pressurizing chamber are partitioned by the third seal, and   the piston has a communication passage that provides a fluid communication between the piston passage and the intermediate chamber.   
     
     
         2 . The reciprocating pump according to  claim 1 , further comprising a shaft seal device configured to seal a gap between a piston rod coupled to the piston and the cylinder. 
     
     
         3 . The reciprocating pump according to  claim 1 , wherein a diameter of the inflow chamber is larger than a diameter of the pressurizing chamber. 
     
     
         4 . The reciprocating pump according to any one of  claims 1 to 3 , wherein the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber are arranged in an order of the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber along a longitudinal direction of the cylinder.